Using Unity's atmospheric scattering

I have found an atmospheric scattering for free on the asset store made by Unity that was used in the Blacksmith short they made.
Problem is, I can’t get it to work.
In my scene I dropped the “Atmo Scattering Deferred” to my camera and set up a light where my sun would be, but nothing happens.
It worths mentioning that I have no skybox and my game is 2d using mesh planes and sprites. As a result I wish to use my old mats (though I tried using the mats provided by Unity and it didn’t work out).
I would like to ask for some help to set up this atmo scattering.
Thanks in advance.

The whole blacksmith environment project is available for download, why don’t you take a look there how it’s setup? They usually provide already setup scenes.